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Vanadium is a refractory metal with high melting point (1910°C) that has good structural strength, good room-temperature corrosion resistance, and low thermal neutron-absorption cross section. Vanadium is primarily used as a steel additive to improve the strength of steels by forming stable nitrides and carbides. Addition of yttrium to vanadium alloys can improve the oxidation resistance and mechanical properties. In this work, three binary systems, V-Ce, V-La, and V-Y, were thermodynamically assessed based on the ASM Binary Alloy Phase Diagrams using CALPHAD approach. Self-consistent thermodynamic descriptions for all three systems were obtained.

Addition of light rare earth elements in small amounts to refractory metal based alloys (e.g., Cr) can increase both ductility and creep resistance of an alloy because the additives absorb residual oxygen in the alloy by forming oxides that can serve as dispersion strengtheners. In this work, three binary systems, Cr-Ce, Cr-La and Cr-Y, were thermodynamically assessed based on limited experimental data available in the literature using the CALPHAD method. Self-consistent and reasonable thermodynamic descriptions for all three systems were obtained. More importantly, two predictions are made: a peritectic reaction in the La-rich side of Cr-La system and a catatectic reaction in the Y-rich side of Cr-Y system. These predictions and the developed databases are subject to future experiments that are needed to clarify several discrepancies in these binaries.

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Molybdenum is a refractory metal that is typically used for high-temperature applications due to its high melting point (2615°C), high-temperature strength, low thermal-expansion coefficient, and high thermal conductivity. The alloying of rare earth elements to molybdenum can help improve oxidation resistance as well as strengthening the alloy via dispersion strengthening due to formation of rare earth oxides. In this study, two binary systems, Mo-Ce and Mo-Y, were thermodynamically assessed based on limited phase equilibria information available in the literature. Self-consistent thermodynamic descriptions for both systems were obtained using the CALPHAD method.